I'm a hair stylist and I'm 25 weeks pregnant. I've talked to my manager and doctor and it's safe just as long as you can handle the smell of ammonia. I color my hair and it's fine the only thing is that your hair may not turn out the same when you're not pregnant. Everyone's hair is different so it may or may not be affected.
If you're really concerned get foils or highlights since that don't touch your scalp
You are also supposed to avoid dyes with ammonia in them.
No it won't hurt the baby
It's never been prove that it hurts the baby. I did mine last week. Make sure if you do it at home, the room is well ventilated. If your completely unsure about it, talk to your Dr.
They say as long as the room is ventilated it's fine some wait untill after the first tri tho
Its better to do it after your baby is fully developed
I've dyed my hair twice since becoming pregnant and I've had a 100% smooth pregnancy I'm 30 wks now. . I know loads of people who dye it have never heard of it actually doing damage